iOS/Android: Zombies, Run! is a mobile app that changes the way you jog or run. Instead of just tracking what you do, it pits you against a world of zombies in a fight to survive. Today it's on sale for $3.99, down from its normal price of $7.99.

We really liked Zombies, Run! when we gave it a spin earlier this year, and it's one of your favorite running apps. That said, the price point of $7.99 is a little high for some people, but $3.99 lessens the blow to your wallet. If you're looking for a fun way to get into running, walking, or jogging, Zombies, Run! certainly fits the bill.